If the idea of Harlequins making their Super League debut against St Helens at The Stoop on Saturday seems fanciful enough, then the background of Quins' new conditioning coach Thibault Giroud stretches credibility further to the limit.

Giroud, 31, a former American football running back who is on first-name terms with Prince Albert of Monaco, used to train with Namibia's Frankie Fredericks and will spend much of the next fortnight watching the Winter Olympics as at the 1998 games he won a bronze as brakeman with France in the four-man bob. "Playing professional sport is good, especially NFL, but it's nothing compared to an Olympics," he reflects, "especially when you get a medal."

Born in France to Tongan parents, Giroud's improbable journey began at the age of 17 in Grenoble. "I was lucky I was running a track meet and there was a scout there from Dartmouth College in the US," he recalls. "He was on holidays but after the race came to me and said do you want to play football. I didn't know what he meant by football, but four months later I had a scholarship.

"I didn't speak any English, didn't know anything about the game, and in my freshman year didn't play much. In my sophomore year I started to play well, then I was drafted by the [New York] Jets."

He never made it in the NFL but after stints in the Canadian league he returned to Europe, playing for Barcelona, Amsterdam and Munich. "Then I broke my leg so I was out for about eight months and I met Prince Albert in a conference about sports, because I was very interested in conditioning already," he says. "Just opportunities, man, all my life's been like that.

"He said 'why don't you try to come to bobsleigh', because he's got his own team in Monaco. I spent a season with them, then the French team came to get me, and later that year I went to the Olympics. From '98 to 2002 we had France's best results ever - world champions in '99, European champions in 2000. But at Salt Lake [in 2002] we had a bad day, and I was done with too much travelling."

Namibia beckoned next. "I had met Frankie Fredericks before, because he was training in Monaco. Frankie was an old-fashioned kind of runner, he reached his velocity after 50 [metres], and all these blokes like Maurice Greene and Ato Boldon were very good off the mark, so he was a bit behind on those.

"The way I was training was quite interesting for [Frankie], all power and explosiveness. So I gave him some tricks for getting out of the start, and after the Olympics he asked me to come to Namibia with him full-time. His first 30 improved a lot, and with him helping me I thought I'd run back in Europe, and got a best of 10.53. You wouldn't make any money from that, but I was happy because my career was behind me anyway."

Besides, Giroud was already heading for rugby. "One time with Frankie we went to Cape Town for training and we met Andre Markgraaf, the ex-Springbok coach. He was watching us train and I said I didn't understand why rugby players didn't train more for power and speed."

Markgraaf called him the next week and Giroud spent more than a year there, with the Leopards and then in Super 12 with the Cats. "But I couldn't take South Africa no more. It's too dangerous, man. Jo'burg was a bit rough for me and my wife. So I signed for Saracens three years ago."

He actually found himself on the wing in a couple of games before moving to Pau last year, but a change in coach meant another change and Giroud was pondering a move to the NFL when the Harlequins post came up."I had been looking at rugby league and thinking it might suit me as a trainer because the players are more physical and athletic, and it is a faster game.

"You need to be big, explosive. You need to be repeating effort at 100% as much as you can for 80 minutes. To reach that maximum velocity after three, four, five steps, not after 10 metres. That's too late. A lot of people think when you're big you cannot be fast, which is not true. If you look at the bobsleigh people they are 110-115kg and can run 30 metres in 3.6sec. That's exactly what you want in rugby league.

"I'm trying to bring stuff from bobsleigh, from the track - if you don't know how to run, you can't run fast - stuff from a lot of weightlifters and a lot of stuff from NFL because agility-wise and power-wise they're ahead of everyone. We've been training for only two months only but I'm very happy with the results in speed, power, explosiveness."

That will be tested to the full against a replenished St Helens, the strongest pre-season Super League favourites for years.

Giroud's CV

1974 born and adopted in Grenoble

1993 drafted as a running back by New York Jets

1995-7 plays NFL Europe for Barcelona, Amsterdam and Munich

1997 joins Monaco bobsleigh team

1998 joins France's four-man bob team for Olympics in Nagano, shares bronze medal with Great Britain